bpftool: add ability to dump BTF types
authorAndrii Nakryiko <andriin@fb.com>
Thu, 25 Apr 2019 22:30:08 +0000 (15:30 -0700)
committerAlexei Starovoitov <ast@kernel.org>
Fri, 26 Apr 2019 04:45:14 +0000 (21:45 -0700)
commitc93cc69004df340d71a9ab3433b8e5c9fd1fca7a
treeacbf09b741504f8bb1a1250e26a4c913d0ab5c18
parent77d764263d1165a2edf13735915fc39bc44abf1d
bpftool: add ability to dump BTF types

Add new `btf dump` sub-command to bpftool. It allows to dump
human-readable low-level BTF types representation of BTF types. BTF can
be retrieved from few different sources:
  - from BTF object by ID;
  - from PROG, if it has associated BTF;
  - from MAP, if it has associated BTF data; it's possible to narrow
    down types to either key type, value type, both, or all BTF types;
  - from ELF file (.BTF section).

Output format mostly follows BPF verifier log format with few notable
exceptions:
  - all the type/field/param/etc names are enclosed in single quotes to
    allow easier grepping and to stand out a little bit more;
  - FUNC_PROTO output follows STRUCT/UNION/ENUM format of having one
    line per each argument; this is more uniform and allows easy
    grepping, as opposed to succinct, but inconvenient format that BPF
    verifier log is using.

Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Yonghong Song <yhs@fb.com>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
tools/bpf/bpftool/btf.c [new file with mode: 0644]
tools/bpf/bpftool/main.c
tools/bpf/bpftool/main.h